Streamflow#

Below you will graphs, maps, and images describing streamflow conditions in the water supply areas during the 2023-24 winter season.

Mean Daily Inflows#

The chart below shows mean daily river inflows for 2024. The range of normal is shown with the gray shaded area, and the historical average is shown with the dashed line. The green and red dashed lines show the 2 and 5 year return flows. It’s important to note, the October atmospheric river event was considered a 1:50 to 1:100 year rainfall event, but the heaviest rains fell south of the Capilano river gauge. Rainfall and inflows were not as exceptional further into the WSAs.

Realtime Inflow Data

You can find realtime inflow data for Capilano River above Lakehead on the Water Survey Canada Hydrometric Data website

Monthly Average Inflows and Statistics#

The plot below shows mean monthly inflows (green dash). The boxplot shows the distribution of values for each month, and the barplot on the right shows the percent of normal inflows. This shows a wet start and end to 2024, and a relatively dry middle of the year. Once again, river inflows were very low during the dry summer months.

Cumulative River Inflows#

The chart below shows the cumulative river inflows for Capilano River above Lakehead. This shows the 2024 water year (Oct. 1 2023 to Sep. 30, 2024). It does not capture the very wet fall weather in 2024; however, the late January atmospheric river is very clear. Overall, the water year saw near-normal river inflows. There were higher than normal flows in the winter due to relatively warm temperatures, and lower than normal flows during the dry summer months.

Summer Low Flows#

The chart below shows average inflows for the summer months (June 1 to September 30). Low summer flows are typically associated with poor snow seasons, which are commonly El Nino years. This plot shows that average summer flows have gradually declined over the past several decades; however, summer flows, like snowpack, are linked to the warm and cool phases of the Pacific Decadal Oscillation (PDO).